NANOCOLD Informe resumido

Parallel mechanical masks

Technological procedures were invented to fabricate serial as well as parallel working devices for shadow deposition of cold atom material on a sub-300nm scale. In case of serial deposition, cantilevers with integrated hollow tip carrying a 100nm aperture were used to deposit and write structures in a scanning vector oriented process. Technology for self-adjusted fabrication of apertures in the three-dimensional tip structure is based on the specific behaviour of carbon fluorine based silicon dioxide plasma etching. The detailed study of clogging behaviour of tips or apertures required parallel writing with arrays of aperture tips or apertures in plane membranes. In particular identifying written structures on plane substrates was substantially facilitated. In a first approach the same aperture tips were arrayed on a plane membrane. However, the geometry of tips (70.5 degree opening angle and 22µm base size) required 25µm spacing between tips to guarantee the mechanical stability of the membrane. Density of tips was substantially increased using conventional e-beam lithography followed by subtracting methods to obtain pierced membranes. In this way 3x3mm² membranes were realized carrying hundreds of apertures.